The actor told Spanish website UOL (via Comic Book Movie) that he has entered negotiations to reprise his role of Persian king Xerxes.

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"It's not a sequel, but does not come before," said Santoro of the movie's premise. "It's a film that takes place at about the same time of the battle that goes on in the first film."

Sullivan Stapleton was previously reported to have been cast as Xerxes in the untitled film, before the actor clarified via Twitter that he will play a hero named Themistocles. Jamie Blackley will portray a Greek named Calisto.

Casino Royale star Eva Green has also been linked to the project, which was in development under the working title of The Battle of Artemisia.

Zack Snyder's 300 was based on the graphic novel by Frank Miller, whose upcoming Dark Horse Comic miniseries Xerxes will provide the inspiration for the follow-up.